Posted: Sun, Mar 17, 2002, 8:49 AM ET (1349 GMT)
A Russian Rockot booster successfully launched two science satellites early Sunday. The Rockot blasted off from the Plesetsk Cosmodrome in northern Russia at 4:21 am EST (0921 GMT) and placed the two Gravity Recovery And Climate Experiment (GRACE) satellites into 500-km polar orbits. The launch was scheduled for Saturday but was delayed by high upper-level winds. The two satellites, nicknamed "Tom" and "Jerry" after two classic cartoon characters, will fly about 200 kilometers apart. Scientists will measure the constantly changing distance between the satellites and use that and GPS-derived position data to map the Earth's gravity field with up to 1,000 times greater precision than previously possible. The GRACE spacecraft also carry atmospheric limb sounder equipment that will be used to provide atmospheric data for weather forecasts. GRACE is a joint project of NASA and the German space agency DLR. The launch, arranged by the German-Russian firm Eurockot, is only the second this year by Russia, although up to three more Russian launches are scheduled for the remainder of this month.